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The capital costs required for Direct Air Capture (DAC) systems to meet the world's climate goals far exceed the global GDP in 2023

Summary​

Direct Air Capture systems require substantial capital investments that vary by technology, with liquid sorbents ($80–$150/tCO₂) currently being cheaper to build than solid sorbents ($200–$1,000/tCO₂). These estimates exclude operational energy costs, meaning actual required investments could be significantly higher. To limit atmospheric CO₂ to 450 ppm by 2100 under the Intergovernmental Panel on Climate Change's (IPCC) Representative Concentration Pathway scenarios, estimated capital costs using lower price estimates (representative of future costs) range from $173.3 trillion to $704.5 trillion for solid sorbents across RCP scenarios - exceeding 2023's global GDP of $106.17 trillion by 1.6x to 7x respectively. Even optimistic projections show most scenarios requiring investments greater than total global economic output.

The capital costs of a DAC system vary depending on the technology used, mainly whether it uses liquid or solid sorbent technology. As a general rule, liquid sorbents tend to have a lower capital cost, while solid sorbents tend to have a lower operational/energy cost. However, the high capital cost of solid sorbents is mainly due to the fact that the technology is still in the early development phase, and the fabrication of the solid sorbents is not yet scalable. Capital cost estimates for DAC systems currently lie between $80–$150/tCO₂ for liquid sorbents and $200–$1,000/tCO₂ for solid sorbents 1. It should be noted that these estimates do not include the additional cost of the energy supplied to produce the components that are considered capital costs.

Capital costs to meet climate goals​

Knowing the capital costs, it is possible to roughly estimate the combined capital cost of DAC systems in the current state to meet an arbitrarily chosen climate goal of "limiting the atmospheric concentration of CO₂ to 450 ppm by 2100" using the International Panel on Climate Change (IPCC) Representative Concentration Pathways (RCPs). From these previous calculations, we can estimate the amount of carbon dioxide (CO₂) that would need to be removed from the atmosphere for the three main RCPs as shown in table 1.

Table 1: Atmospheric CO₂ removal required to achieve 450 ppm or less for each RCP scenario

ScenarioProjected 2100 CO₂ concentrations (ppm)Estimated average global temperature Rise Range (°C)CO₂ Removal required (Gt)
RCP 2.64000.9 – 2.41300
RCP 4.55251.7 – 3.3866.4
RCP 8.59003.2 – 5.73522.6

From these values, we can estimate the capital cost of DAC systems to meet each of the RCPs for solid and liquid sorbents by multiplying the amount of CO₂ removed by the capital cost per tonne of CO₂. For this analysis, we will assume that the capital costs for each technology are their lower estimate of $80/tCO₂ for liquid sorbents and $200/tCO₂ for solid sorbents. These capital costs are expected to decrease as the technology matures and scales up, so using the lower estimate will yield a result closer to those expected values.

 Capital cost≈Amount of CO2 removed [Gt]×109×Capital cost per tonne of CO2 [$/tCO₂]\begin{align*} \text{ Capital cost} &\approx \text{Amount of CO}_2 \space \text{removed [Gt]} \times 10^9 \times \text{Capital cost per tonne of CO}_2 \text{ [\$/tCO₂]} \\ \end{align*}

Table 2: Estimated capital costs for DAC deployment by scenario and sorbent type

ScenarioSorbent TypeCapital Cost (USD trillion)
RCP 2.6Liquid Sorbents$104
Solid Sorbents$260
RCP 4.5Liquid Sorbents$69.3
Solid Sorbents$173.3
RCP 8.5Liquid Sorbents$281.8
Solid Sorbents$704.5

Comparison to global Gross Domestic Product (GDP)​

In 2023, the World Bank estimated the global GDP (the total value of all goods and services produced by the whole world) to be $106.17 trillion USD 2. This would mean that for all but one scenario (RCP 4.5 utilizing liquid sorbents), the capital cost required to meet the climate goal would be greater than the global GDP in 2023 and can reach as high as 7x the global GDP for the RCP 8.5 scenario, all under the assumption that the capital costs are at their lower estimate.

Sources​

Footnotes​

  1. Ozkan, M., Nayak, S. P., Ruiz, A. D., & Jiang, W. (2022). Current status and pillars of direct air capture technologies. iScience, 25(4), Article 103990. https://doi.org/10.1016/j.isci.2022.103990 ↩

  2. World Bank. (n.d.). World development indicators: GDP (current US$) [World development indicators: GDP (2023)]. Retrieved [January 13, 2025], from https://databank.worldbank.org/reports.aspx?source=2&series=NY.GDP.MKTP.CD&country=#advancedDownloadOptions ↩